Amid the chaos of a 1937 air-raid drill in Nanjing, underground operative Zhou Mo, code-named “Watchmaker,” witnessed a liaison being assassinated.
> With his dying breath, the liaison pressed half a jade pendant into his hand. “Find ‘Butterfly’... Stop the ‘Cherry Blossom Festival’...”
> At almost the same time, Jewish codebreaking expert Anna fled to Nanjing, where the Japanese Kempeitai were after the codebook her father had entrusted to her before he died.
> Meanwhile, Jin Xiaodao, a Green Gang thug, was drawn by chance into a plot involving a secret Japanese biological weapons depot after his master was kidnapped.
> The three strangers were each carrying out missions that seemed entirely unrelated:
> Zhou Mo followed the trail of the jade pendant and discovered that “Butterfly” was connected to a secret scandal within the Japanese imperial family.
> Anna’s decrypted message pointed to the same depot, bringing the full fury of the Kempeitai down on her.
> Trying to save his master, Jin Xiaodao accidentally set off the chain of events that ignited the depot.
> When the explosion lit up the Yangtze, the three stared at one another in astonishment. Their operation code names were all “Butterfly.”
